If you transfer URs to an airline program it's usually at 1:1, but for the flights we've booked it's so much cheaper that way. This is for J-class to Europe, not domestic coach. The flight I just took home cost $8,000 one way (yeah, that's crazy), so it would have been a ton of URs through the Chase portal, even with the 1.5 redemption on the CSR. Alternatively, it was 56K Flying Blue points, which meant it was 56K URs.
We stalk the flights before they open (so a couple of weeks before) and see what flights look good, which ones take URs or MRs as transfer points, then check to see what the points cost + taxes and fees are. Those taxes and fees really add up when flying J or first. If you find something that looks good, figure out what time/day those flights are released and be ready. If they pop up, and have available seats on points, you can transfer the URs and grab them.
There are different things to consider - then you can figure out what works best for you. Lately I've been avoiding any stops at LHR (even with the great MR>Avios deal out there) because the taxes and fees are pretty much the price of a coach flight.
Also, while I'd love to try different airlines and go with whatever seems the fanciest, I'm also a "bird in the hand" kind of person, so I pretty much grab whatever is acceptable and available (for me it's lie flat) instead of waiting to see if something better comes along.
As
@tink1970 said above, getting to/from Edinburgh is a little complicated. I do think the train looks nice. We were thinking about going there after our cruise next summer, but getting to/from CDG is just so much easier for us, so we'll fly from there instead. That will depend on which airport you're flying out of and what your options are.
I hope this helps. Please ask your questions here - I'm not an expert, but I'll try to help and I'm sure others will, too. It's a bit nerve-wracking when doing it, but if you are flexible I think you will find something that works for you.